资源环境科技发展态势分析平台

Because Earth's soil contains more carbon than the atmosphere and all terrestrial vegetation combined, forecasting and managing the global carbon cycle in the face of natural and anthropogenic change requires accurate representations of this carbon. Here from regional geomorphic and soil databases, we characterize the mass, distribution, and cycling of previously unaccounted for soil carbon across the southeastern U.S. Coastal Plain, referred to as "deep-podzolized carbon." We show that geomorphologic-hydrologic interactions stabilize approximately 1.1 x 10(-9) t of deep-podzolized carbon (equivalent to roughly 18% of the soil organic carbon stored across the entire region from 0-30 cm), and that this potentially ancient carbon is predictably distributed coincident with Pleistocene marine transgressions. We not only redefine soil carbon storage in the region but we also introduce the Earth Sciences to a massive organic carbon pool that interacts with landscape evolution and hydrology, has essentially never been studied, and is ripe for interdisciplinary research.

Plain Language Summary Soils can accumulate and store tremendous amounts of carbon from the atmosphere. Subsequently, Earth scientists have been keenly focused on soil carbon for decades with the aim of mitigating, forecasting, and managing climate change. Here for the first time, we characterize the mass, distribution, and cycling of a billion tons of soil carbon in the southeastern U.S. Coastal Plain that until now had evaded detection. We refer to this clandestine carbon as "deep-podzolized carbon." We show that deep-podzolized carbon is predictably distributed across the region and that it is transported and stabilized belowground by hydrologic processes. While the Coastal Plain is already recognized as a "hot spot" for soil carbon storage, our work indicates that the region stabilizes appreciably more carbon than previously thought, and suggests that future quantification of soil carbon may require observations that extraordinary deep. We expect that further characterization of deep-podzolized carbon will help identify new strategies to promote soil carbon accumulation.